Power lift for tractors



y 1936- E. A. JOHNSTON 2,039,316

POWER LIFT FOR TRAGTORS Filed May 22, 1935 4 Shee ts--$heet 1 May 5, 1936. JQHNSTON 2,039,316-

POWER LIFT FOR TRACTORS Filed May 22, 1935 4 Sheets-Sheet 2 May 5, 1936. E. A. JOHNSTON POWER LIFT FOR TRACTORS 4 Sheets-Sheet s 7 Filed May 22, 1955 Mdon , y 1 E. A. JOHNSTON 2,039,316

POWER LIFT FOR TRACTORS Filed May 22, 1955 4 Sheets-Sheet 4 Patented May 5, 1936 POWER LIFT FOR TRACTOBS Edward A. Johnston, Chicago, Ill., assignor to International Harvester Company, a corporation of New Jersey Application May 22, 1935, Serial No. 22,890

16 Claims.

The present invention relates generally to farm tractors for propelling, carrying, and operating agricultural implements, and more specifically to power operated lifting devices.

The fundamental object of the invention is to provide improved mechanism mounted on the tractor and driven by power derived from the engine for lifting. lowering or otherwise adjusting implements, such as plows and cultivators, 10 attached to or operated by the tractor.

More specifically, one object of the invention is to provide a power lift mechanism which is hydraulically actuated. Another object subsidiary to said object is to provide an improved and simplified two-way acting hydraulic mechanism.

Another object is to provide a hydraulic mechanism which may be constructed to move an operating lifting shaft through substantially more than a half revolution, whereby the crank may 20 be connected to lifting members to move past dead center in either of two positions.

Another object is to provide a hydraulic lifting mechanism particularly adapted to the oscillation of a crank of rockshaft for use in lifting implements.

The above objects and others, which will be apparent from the detailed description to follow, are accomplished by the mounting of a hydraulic mechanism of a narrow piston type, the piston being mounted in a cylinder for reciprocation by the application of pressure at either end of the piston. The lifting member in the form of a rockshaft is connected to and moved by the piston by means of a rack formed on the piston and a gear carried by the shaft. A hydraulic pump is mounted on the tractor in any suitable position for supplying operating liquid under pressure to the hydraulic mechanism. A suitable control valve and properly located conduits are provided for delivering the high pressure liquid to either end of the piston and for allowing the escape of liquid simultaneously from the other end of the piston. In order to provide a mechanism in which the supply of high pressure liquid is rendered ineffective after the piston has completed its stroke, valve means are utilized, which are automatically operable by movement of the piston into its respective positions of rest at the end of its strokes in each direction.

In the drawings:

Figure 1 is a plan view of the rear portion of a conventional tractor, on which a power lift incorporating the invention is mounted;

Figure 2 is a side elevation of the same structure shown in Figure 1 with one axle housing broken away to better show the power lift mechamsm;

Figure 3 is a plan view of the power lift casing with the valve housing broken away upon a horizontal section, to illustrate the operation of the valve;

Figure 4 is a transverse vertical section taken on the line 4-4 of Figure 3; v

Figure 5 is a'horizontal section taken on the line 55 of Figure 6;

Figure 6 is a longitudinal vertical section taken on the line 6-6 of Figure 3; and,

Figure 7 is a transverse vertical section taken on the line 11 of Figure 1, showing only the power lift mechanism.

Only the rear portion of a tractor has been shown as the power lift mechanism incorporating the invention may be used on any of the conventional types of farm tractors. Thetractor illustrated has a frame In connected to a transversely extended rear axle housing I i. Depending housings I2 at the end of the housing ll contain the driving mechanism for traction wheels I3. The rea'r portion of an engine I4 is shown mounted on the frame H). The transmission casing I5 at the rear of the frame I is spaced a substantial distance rearwardly from the rear end of the engine I 4. A gasoline tank I is mounted above the frame between the transmission casing and the engine, being supported in position by upstanding brackets ID. A substantial space remains between the tank i5 and the frame Ill and longitudinally between the brackets I0. It is in this The power lift casing It extends in a longitudinal direction with respect to the tractor and is positioned adjacent one side of the frame ill in the space between the engine and the transspace that the power lift mechanism ismounted.

mission casing. Said casing is of a cross section.

as best shown in Figure 7. Aligned bores I] are formed at each end of the casing i6 into which a cylinder I8 is fitted, with the ends of the cylinder flush with respect to the ends of the casing.

A piston I9 is mounted for reciprocation inthe inwardly extending boss 2| formed with a bore 22.

A transversely extending lifting shaft 23 extends through the bore 22. At the other side of. the casing, a housing 24 is secured to the casing over an opening 25. The casing 24 is provided with an extension 28 within the casing IS. A bore 2.! 1 formed in the extension 26 is in alignment with length, a past dead center lock may readily be provided for with only slightly more than 180 degrees movement of the lifting cranks.

Although applicant has shown and described a preferred embodiment of his improved hydraulic lift mechanism, it is to be understood that he claims as his invention all modifications falling within the scope of the appended claims.

What is claimed is:

1. A power lift device for tractors comprising, in combination with a tractor and an implement to be lifted, a rockshaft mounted on the tractor, lifting connections between the rockshaft and the implement, a power actuated shaft mounted on the tractor, a lifting lever arm connected to said shaft, a lifting member connecting said lever arm and rockshaft, and means for operating the lifting shaft through an angular movementof substantially more than 180 degrees whereby the lever arm may be moved to a past dead-center position in either of its extreme positions.

2. A power lift device for tractors comprising, in combination with a tractor and an implement to be lifted, a transverse rockshaft mounted on the tractor at the rear thereof, lifting connections between the rockshaft and the implement, a power actuated shaft mounted on the tractor spaced forwardly from the rockshaft, a lifting lever arm connected to said shaft, a longitudinal lifting member capable of transmitting tension and compression connecting said lever arm and rockshaft, and means for operating the lifting shaft through an angular movement of substantially more than 180 degrees whereby the lever arm may be moved to a past dead-center position in one extreme position with the lifting member under tension and to a past dead-center position in the other position with the lifting member in compression.

3. A power lift device for tractors comprising, in combination with a tractor and an implement to be lifted, a transverse rockshaft mounted on the tractor, lifting connections between the rockshaft and the implement, a power actuated shaft mounted transversely on the tractor, a lifting lever arm connected to said shaft, a lever arm on the rockshaft, a lifting member of substantial length with respect to the length of the lever arm connecting said lever arm and lever arm on the rockshaft, whereby movement of said member is substantially rectilinear, and means for operating the lifting shaft through an angular distance of substantially more than 180 degrees whereby the lever arm may be moved to a past dead-center position in either of its extreme positions.

4. A power lift device for tractors comprising, in combination with a tractor and an implement to be lifted, a transverse rockshaft mounted on the tractor, lifting connections between the rockshaft and the implement, a power actuated shaft mounted transversely on the tractor, a lifting lever arm connected to said shaft, a lever arm on the rockshaft, a lifting member of substantial length with respect to the length of the lever arm connecting said lever arm and lever arm on the rockshaft, whereby movement of said member is substantially rectilinear, and a two way hydraulic piston operable to rock the lifting shaft through an angular distance of substantially more than 180 degrees whereby the lever arm may be moved to a past dead-center position in either of its extreme positions.

5. A power lift device for tractors comprising, in combination with a tractor and an implement to be lifted, a transverse rockshaft mounted on the tractor, lifting connections between the rockshaft and the implement, a power actuated shaft mounted transversely on the tractor, a lifting lever arm connected to said shaft, a lever arm on the rockshaft, a lifting member capable of transmitting tension and compression of substantial length with respect to the length of the lever arm connecting said lever arm and the lever on the rockshaft whereby movement of said member is substantially rectilinear, and means for operating the lifting shaft through an angular movement of substantially more than 180 degrees whereby the lever arm may be moved to a past dead-center position in one extreme position with the lifting member under tension and to a past dead-center position in the other position with the lifting member under compression.

6. A power lift device for tractors comprising, in combination with a tractor and implement connected thereto, a casing mounted. on the tractor, a transverse rockshaft extending through said casing, lifting connections between said shaft and the implement, a cylinder formed in said casing, a piston mounted for reciprocation in said cylinder, a rack formed along one side of the piston, a gear mounted on the rockshaft and positioned for engagement with said rack, and means to supply fluid under pressure to the cylinder.

7. A power lift device for tractors comprising, in combination with a tractor and implement connected thereto, a casing mounted on the tractor, a transverse rockshaft extending through said casing, lifting connections between said shaft and the implement, a cylinder formed in said casing, a piston mounted for reciprocation in said cylinder, valve means for supplying fluid under pressure to either end of said piston, a rack formed along one side of the piston, a gear mounted on the rockshaft and positioned for engagement with said rack whereby reciprocation of the piston oscillates the rockshaft, and means operated by the tractor engine to supply fluid under pressure to the valve means.

8. A power lift device for tractors comprising, in combination with a tractor and implement connected thereto, a casing mounted on the tractor, a transverse rockshaft extending through said casing, lifting connections between said shaft and the implement, a cylinder formed in said casing, a two-way piston mounted for reciprocation in said cylinder, a rack formed along one side of the piston, a gear mounted on the rockshaft andpositioned for engagement with said rack, and means to supply fluid under pressure to the cylinder at either end of the piston.

9. A power lift device for tractors comprising, in combination with a tractor and implement connected thereto, a casing mounted on the tractor, a transverse lifting shaft extending through said casing, lifting connections between said shaft and the implement, a cylinder formed in said casing, a two-way piston mounted for reciprocation in said cylinder, a rack formed along one side of the piston, a gear mounted on the rockshaft and positioned for engagement with said rack, and means to supply fluid under pressure to the cylinder at either end of the piston, the movement of said piston being a distance suflicient to rock the lifting shaft substantially more than 180 degrees.

10. A power lift device for tractors comprising, in combination with a tractor and implement connected thereto, a casing mounted on the tractor, a transverse rockshaft extending through said casing, lifting connections between said shaft and the implement, a cylinder formed in said casing,

a piston mounted for reciprocation in said cylinder, valve means for supplying fluid under pressure to either end of said piston, and for simultaneously draining fluid from the other end. a rack formed along one side of the piston, a gear mounted on the rockshaft in engagement with said rack whereby reciprocation of the piston oscillates the rockshaft, and means operated by the tractor engine to supply fluid under pressure to the valve means.

11. A power lift device for tractors comprising, in combination with a tractor and an implement to be lifted, a transverse rockshaft mounted on the tractor, lifting connections between the rockshaft and the implement, a lifting crank pivotally mounted on the tractor on a transverse axis spaced longitudinal of the tractor from the rockshaft, a lifting arm on the rockshaft, a lifting member capable of transmitting tension and compression connected, to said arm and the lifting crank, and power operated means for rocking the lifting crank substantially more than 180 in opposite angular directions whereby the point of connection of the lifting member with the lifting crank may be moved past dead-center position in either direction with respect to the center line of the axis of the crank and the pivot axis of the lifting member on the lifting arm.

12. A power lift device for tractor comprising, in combination with a tractor and an implement to be lifted, a transverse rockshaft mounted on the tractor, lifting connections between the rockshaft and the implement, a lifting crank pivotally mounted on the tractor on a transverse axis spaced longitudinal of the tractor from the rockshaft, a lifting arm on the rockshaft, a lifting member capable of transmitting tension and compression connected to said arm and the lifting crank, and a two-way hydraulic device operable to rock the lifting crank substantially more than 180 in opposite a ular directions whereby the point of connection of the lifting member with the lifting crank may be moved past dead-center position in either direction with respect to the center line of the axis of the crank and the pivot axis of the lifting member on the lifting arm.

13. A power lift device for tractor comprising in combination with a tractor and an implement to be lifted, a transverse rockshaft mounted on the tractor, lifting connections between the rockshaft and the implement, a lifting crank pivotaily mounted on the tractor on a transverse axis spaced longitudinal of the tractor from the rockshaft, a lifting arm on the rockshaft, a lifting member capable of transmitting tension and compression connected to said arm and the lifting crank, a casing mounted on the tractor, a lifting shaft extending into the casing, and a two-way hydraulic piston within the casing for rocking said shaft substantially more than 180 degrees in either angular direction, the lifting crank being secured to said shaft in a position whereby the point of connection of the lifting member with the lifting crank may be moved past dead-center position in either direction with respect to the center line of the axis of the crank and the pivot axis of the lifting member on the lifting arm.

14 In a fleld implement, the combination with a traveling support and a tool carrying member adjustably connected thereto, of a casing mounted on the support, a piston mounted in said casing for oscillation therein, means for delivering fluid under pressure into the casing at either side of the piston and for simultaneously removing fluid from the other side, a lifting shaft mounted on the support, lifting connections between said shaft and the earth working member, and power transmitting connections between said shaft and the piston operable by actuation of the piston to rock the shaft in opposite angular directions substantially more than 180 degrees whereby an overdead-center lock may be provided in either extreme position.

15. In a field implement the combination with a tool carrying member and-a traveling support therefor, of a casing mounted on the support, a piston oscillative in said casing, means for delivering fluid under pressure at a substantially continuous rate to either side of the piston, means operated by movement of the piston for by-passing fluid being supplied to the high pressure side when the piston reaches the end of its stroke in either direction and lifting connections between the piston and the tool carrying member.

16. In a field implement the combination with a tool carrying member and a traveling support therefor, of a casing mounted on the support, a piston oscillative in saidcasing, means for delivering fluid under pressure at a substantially continuous rate to either side of the piston, means operated by movement of the piston for by-passing fluid being supplied to the high pressure side when the piston reaches the end of its stroke in either direction and lifting connections between the piston and the tool carrying member, said connections including a rockshaft actuated by the piston to move substantially more than 180 degrees in opposite angular directions.

EDWARD A. JOHNSTON. 

